Breech mechanisms for open-chamber guns



3 Sheets-Sheet l INVENTOR. DA v/o DA/w/cK 47, jikpym wr ke ATTORNEYS.

April 1 D. DARDICK 2,831,401

I BREECH MECHANISMS FOR OPEN-CHAMBER GUNS Fil ed Sept, 27 1955 3 Sheets-Shee't 2 INVENTOR. DAV/D DARD/CK A TTORNE Y5 April 22, 1958 D. DARDICK BREECH MECHANISMS F R OPEN-CHAMBER cums 3 Sheets-Sheet 3 Filed Sept. 27, 1955 me Mr D y w A TTORNE Y5.

of the invention.

. 2,831,401 Bunsen MECHANEglENFSOR dPEN-CHAMBERu David Dardicir, New York, N. assignor to Dardiclr This invention relates to open-chamber guns and relates more particularly to open-chamber gunsfor use with l so-called high pressure ammunition.

Objects and. advantages of-(the invention will be set forth in part hereinafter and in part will be obvious herefrorn, or may be learned by practice, with the inven- "tion, the same being realizedfa'nd attained by means and instrumentalities of the combinations, improvements pointed out in the appenddclairns. t

The invention consists in the novel parts, constructions,

arrangements and combinations and improvements here in shown and described. 4 r

The accompaying drawings, referred to herein and f constituting a part hereof, illustrate one embodiment of the apparatus for carrying out the invention, and to gether with the description, serve to explain the principles It is among theparticular objects of this invention to minimize sticking, jamming andgother. difficulties attendant upon expansion of the ca'sesofhigh' pressure ammunition when fired in open-chamber guns, and to .enable the open-chamber rotary drum of the gun to be rotated for ejection of expanded ammunition cases with the same case and facility as it may be when loaded with unfired ammunition, and with substantially no greater power requirement for effecting the rotation.

In accordance with this invention, the frame of the gun which serves as a breech for the open-chamber rotary drum is constructed and arranged to provide in and'as a part thereof, one or more displaceable breech portions. Each such breech portion is of a configuration to provide longitudinally of the drums rotational axis a breech surface of cylindrical contour which is concentric with the drum and is suitably dimensioned in directions normal to and longitudinally of the rotational axis of the drum,

the displaceable breech portion to be moved outwardly and away from the rotary drum in one direction and vice versa. To this end also, the mounting of the displaceable breech portion in the relatively stationary portion of the frame is such that the breech portion is capable of limited back and forth sliding movement relative to the stationary surface in a circular path concentric with the rotational axis of thefope'ni-chainber rotary drum of the gun. Thus, with a shell or' cartridge case expanded in an open-chamber in battery position into tight frictional engagement with the breech surface, r0- tation of the rotary drum in one direction will be resisted by the wedging action of the displaceable breech portion but rotation in the opposite direction will effect a movement of the displaceable breech portion inthe same direc- H 2,831,41 Patented Apr. 22, 1958 [tion along the inclined bearing surfaceand away from the'expanded surface, thus eliminating the frictional resistance or drag of the expanded case on the breech-at thevery beginning of the rotation and freeing the case for easy mechanical ejection upon further rotation of the drum. Means are provided for yieldably opposing the freeing movement of the displaceable breech portion and automatically returning the breech portion to its normal starting position as soon as the expanded shell or case no longer exerts any frictional drag on. it.

Of the drawings: 2 I

Fig. 1 is a view in end elevation of the breechvand rotary drum of a two barreled open-chamber 'gun embodying this invention, as seen from the breech end of the "gun;

Fig. 2 is a fragmentary view in side elevation with parts i in" section of the embodiment of Fig. 1 and,

Fig. 3 is a view in section taken along the line 3+3 of Fig. "2, but with a shell or cartridge in an open-charm scription and thefollowing detailed descriptionas well are exemplary and explanatory of theinvention but 'are not restrictive thereof.

Referring now more particularly to the drawings, a rotary drum ll of cylindrical contour having open chambers 2,13 and 4 is mounted for rotation in a strong and rigid rectangular stationaryframe 5 which serves as a breech for the open chambers. Aligned stub axles'fi and 7 carried by the frame 5 atfront and rear, serve to support the drum for rotation on its, cylinder axis. The breech frame 5'as shown is provided with a removable breech'rail' 8 firmly secured to the top and bottom rails 9'and :10, respectively, as by bolts 11, for facilitating assembly of the rotary drum in thestationaryframe but it will be understood that the framemavbe of unitary integral construction.

Upper and lower gun barrels 12 and 13, respectively, are screwed intothe front railIt-tof the frame, the respective axes of the barrels and the cylinder of the drum lying in a common plane.

barrels; As shown inFig. 3, the chamber 2 is in firing or battery position in alignment with the upper barrel, a shell or cartridge having the case 15 being situated in. the chamber. In suchcase, chamber 3 is in position to be loaded and chamber 4 is in position for the ejection of a discharged shell (not shown).

The breech frame 5 is constructed. and arranged to provide in and as part of its upper rail 9, a displaceahle breech portion 16, a corresponding displaceable breech portion 17 being provided in the lower rail' 10.

The displaceable breech portion 16 is of a configuration to provide a breech surface 18 of cylindrical contour which is concentric with the rotary drum 1 and is dimensioned in directions normal to and longitudinally of the rotational axis of the drum, to span the open chamher 2 whenaligned in battery position with the upper gun barrel 13, as shown in Figs. 1 and 3.

It will be understood that the breech surface 18 has a radius of curvature only slightly larger than the radius of curvature R of the drum 1 so that the opposing surface 39 l of the shell case 15 will be in substantially wiping engagement with the breech surface 18 before firing. After firing, the expansion of the case 15 may result in the case surface 19- being in tight frictional engagement with the breech surface 18, particularly with high pressure ammunition.

assnsor A The displaceable breech portion 16 islalso of a configuration to provide a bearing surface 20 inclined to the breech surface 18 and in sliding engagement with a complementary bearing surface 21 of the top rail 9 of the bearing surface 20 as here preferably embodied is a portion of a circular are having, preferably, substantially the same radius of curvature as the drum 1, but a different center. The complementary bearing surface 21 of the frame has substantially the same radius of curvature as the breech surface 20 so as to obtain a smoothly sliding fit between the two surfaces.

Means are provided. for limiting the extent of movement of the breech portion 16 in either direction of rota- For convenience, the thick edge of the tapered is of a configuration to provide a pair of U-shaped grooveforming portions 22, one at each end and preferably in- J tegral therewith, whose grooves 23 slidably receive a pair of stationary tongues 24, one in each groove, in- I tegral with the upper breech rail 9. The mating surfaces of the grooves 23 and tongues 24 are suitably curved to permit free relative movement therebetween asthe breech portion 16 is displaced on its rotational axis. Likewise the grooves 23 and tongues 24 are of a depth and length, respectively, such that clockwise movement of the displaceable wedge portion 16 is limited to a predetermined amount only sufiicient to free the wedge portion from the underlying case 15 in chamber 2.

The leading edge of the displaceable breech portion 16 is provided with a pair of stop members 25, one at each end of the breech portion, and preferably detachably connected to the leading edge as by screws 26. Advantageously, each stop member may be of L-shaped configuration, as shown, one arm of the L being disposed and arranged so as to abut against the stationary portion of the upper rail 9 in the normal at rest position of the breech member shown in Fig. 1.

A flexible resilient restoring member 27 is secured cantilever-wise between the stationary frame 1 and a removable clamping plate 28 by means of screws 29 passing through the clamping plate into the upper rail 9 of the frame 1, the free end 30 of the restoring member bearing against the leading edge of the breech portion and yieldably holding the breech portion firmly against clockwise movement as viewed in Fig. 2.

The lower displaceable breech portion 17 is in all respects identical with the upper breech portion 16 and serves in the same way to overcome jamming and sticking of an expanded case of a cartridge or shell against the breech frame 1 of the gun when the succeeding chamber 3 is loaded with a round of ammunition, the drum rotated clockwise to bring chamber 3 into firing position in alignment with the lower gun barrel 14, and the ammunication fired. Accordingly thecorresponding parts of the breech portion 17 and its associated parts and members are designated by the same reference characters as are applied to the upper breech member 16, but with the reference characters primed.

In the operation of the open-chamber gun of Fig. 3, it may be assumed that the shell situated in the chamber 2 has been fired and the case 15 expanded so that it is not only in tight engagement with the walls of the chamber 2 but has its surface 19 in tight engagement with the breech surface 18 of the displaceable breech portion 16. Under these conditions a clockwise movement of the rotary drum 1 toward a position at which the chamber 2 would be completely uncovered so as to permit of ejection of the empty shell case therefrom, would initiate a simultaneous clockwise movement of the displaceable breech portion 16 by reason of the frictional drag exerted by the surface 19 of the expanded shell case 15 on the breech surface 18. This clockwise movement of the, breech portion though yieldably opposed by the spring member 27 is accompanied by a radially outward movement of the breech portion as the inclined movable bearing surface 20 slides downhill on the complementary stationary bearing surface 21. This outward movevment effectively frees the surfaces 18 and 19 from each other permitting the drum to be rotated freely to bring the chamber 3 into alignment with the lower barrel 13 and the chamber 2'into position for ejection of the empty case 15. The spring member 27 acting through its free end 30 on the leading edge of the breech portion 16 serves to return the latter automatically to its starting position so soon as the drag exerted by the expanded case drops below the restoring force exerted by the spring member on the breech portion. Movement of the breech portion isof course kept within predetermined limits clockwise by the stop members 22, and by the stop members 25 in the opposite direction.

'in alignmentwith the upper or lower barrel as the case may be. Likewise suitable rotating and indexing means (not shown) are provided for effecting timed rotation of the rotary drum 1 into successive loading, firing and ejecting positions for the upper and lower barrels, alternately. Such means form no part of the present invention and are omitted for the sake of clarity. It will be understood also that although the embodiment of an open-chamber gun herein described and shown has two barrels, the invention is equally applicable to single barrel open-chamber guns and to multiple barrel openchamber guns having more than two barrels.

The invention in its broader aspects is not limited to the specific combinations, improvements and intrumentalities described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. In an open-chamber gun, a rigid breechframe and an open-chamber rotary drum of cylindrical contour journalled for rotation in said breech frame, said frame comprising a relatively stationary breech portion spaced from the cylinder surface of said drum, and a displaceable breech portion interposed in the space between said stationary breech portion and said drum, said displaceable breech portion having a breech surface of cylindrical contour concentric with and of substantially the same radius of curvature as said drum dimensioned to span an open chamber of the drum, when the chamber is in its firing position, and having a bearing surface inclined to said breech surface, said bearing surface being in sliding engagement with acomplementary bearing surface of said relatively stationary breech portion.

2. In an open-chamber gun, a rigid breech frame and an open-chamber rotary drum of cylindrical contour journalled for rotation in said breech frame, said frame comprising a relatively stationary breech portion spaced from the cylinder surface of said drum, and a displaceable breech portion interposed in the space between said stationary breech portion and said drum, said displaceable breech portion having a breech surface of cylindrical contour concentric with and of substantially the same radius of curvature as said drum dimensioned to span an open chamber of the drum, when the chamber is in its firing position, and having a bearing surface inclined to said breech surface, said bearing surface being a surface of cylindrical contour eccentric to said drum and being in sliding engagement with a complementary bearing surface of. said relatively stationary breech portion.

3. In an open-chamber gun, a rigid breech frame and an open-chamber rotary drum of cylindrical contour journalled for rotation in said frame, said frame comprising a relatively stationary breech portion spaced from the cylinder surface of said drum, and a displaceable breech portion interposed in the space between said stationary breech portion and said drum, said displaceable breech portion being tapered to form a' Wedge, having a breech surface of cylindrical contour concentric with and of substantially the same radius of curvature as said drum dimensioned to span an open chamber of the drum, when the chamber is in its firing position, and having a' bearing surface inclined to said breech surface, said bearing surface being in sliding engagement with a complementary bearing surface of said relatively stationary breech portion.

4. In an open-chamber gun, a rigid breech frame; an open-chamber rotary drum of cylindrical contour journalled for rotation in said frame, said frame comprising a relatively stationary breech portion and a displaceable breech portion, said displaceable breech portion being tapered to form a wedge, having a breech surface of cylindrical contour concentric with said drum and having a bearing'surface inclined to said breech surface, said bearing surface being in sliding engagement with a complementary bearing surface of said relatively stationary breech portion; and, means for releasably maintaining said displaceable breech portion in a position of rest between said stationary breech portion and said openchamber drum and for restoring the same to said position after displacement therefrom.

5. In an open-chamber gun according to claim 4, in which said maintaining-restoring means comprises flexible resilient means carried by said stationary breech portion and engaging said displaceable breech portion for yieldably opposing displacement of said displaceable breech portion in one direction from said position of rest and for restoring the same to said position after displacement therefrom.

6. In an open-chamber gun, a rigid breech frame; a

a pair of gun barrels carried by said frame in parallel relation to each other; an open-chamber rotary drum journalled for rotation in said frame, said drum having a plurality of open-chambers disposed and arranged therein for alignment respectively in firing position with said barrels alternately, said frame comprising a'pair of stationary breech portions and a pair of displaceable breech portions, one for each of said stationary portions, said displaceable breech portions each being of a configuration to form a displaceable wedge positioned between the stationary breech portion associated therewith and said open-chamber rotary drum; and, means for releasably maintaining each said displaceable breech por- .6 tion in its position between its associated stationary breech portion and said rotary drum and for restoring the same to said position after displacement therefrom, whereby on rotation of said drum friction between the case of a discharged shell or cartridge expanded between said drum and either of said displaceable breech portions may cause displacement of said breech portion to free said case for ejection from said drum.

7. In an open-chamber gun, a rigid breech frame and an open-chamber rotary drum of cylindrical contour journalled for rotation in said frame, said frame comprising a relatively stationary breech portion spaced from the cylinder surface of said drum, and a release wedge mounted in the space between said stationary breech portionand said drum for bodily displacement in said space relative to said stationary portion and said drum in a transverse plane at right angles to the rotational axis of said drum, said release. wedge and said stationary portion having complementary surfaces providing bearing surfaces therebetween, and said release wedge having a separate breech surface of cylindrical contour concentric with and of substantially the same radius of curvature as said drum, said breech surface being dimensioned to span an open chamber of the drum when the chamber is in its firing position.

8. In an open-chamber gun according to claim 7, means carried by said relatively stationary portion fixing said release wedge against displacement in said plane in one direction from a position of rest between said stationary breech portion and said drum, and separate means also carried by said relatively stationary breech portion for releasably maintaining said displaceable breech portion in said position of rest and for automatically restoring it thereto after displacement therefrom.

9. In an open-chambered gun according to claim 7, said release wedge being tapered in said plane, and having its thick or leading edge disposed to advance in the normal direction of rotation of said drum.

10. In an open-chamber gun according to claim 7, said release wedge having an arcuate breech surface concentric With said drum.

11. In an open-chamber gun according to claim 10, said release wedge having an arcuate bearing surface separate from said arcuate breech surface and eccentric to said drum, and said stationary breech portion having a bearing surface complementary to said arcuate bearing surface and in sliding engagement therewith.

References Cited in the file of this patent FOREIGN PATENTS 471,995 France July 24, 1914 

